[K12OSN] Hostraid and ltsp 4.0.1

Robert Arkiletian robark at telus.net
Wed Oct 6 01:40:15 UTC 2004

Mark Gumprecht wrote:

> I have  a intel server board SE7501HG2. Can the host raid be setup for 
> the 4.0.1 release to get raid 0/1. Or do you have to select 
> non-hostraid drivers? I've looked at intel and adaptecs' website and 
> they say only up to rh9 is supported. Is it possible to have a 
> hardware raid on this mobo or not?
> Mark
I got this board as part of my system for my school. It has been 
excellent. It has an excellent Adaptec SCSI controller on board 
(aic7902). However, Linux does NOT support Host Raid. Host raid is 
actually software raid for Windows (ITS NOT HARDWARE RAID). There are 
drivers for Windows to make it work but not for Linux. However, the 
linux kernel will support software raid using LVM, which is just as fast 
as some hardware raid setups. (Although I have not tried it, I know it's 
done when you setup your partitions) The beautiful aspect of this MB is 
that is has TWO scsi channels. So you can even have the full throughput 
of each channel and raid them through the kernel. All I did was use one 
scsi drive for / and another for /home. I have not tried raid. I'm using 
k12ltsp 3.1.2 (redhat 9) and not 4.0.1 (FC1) because I need stable SMP 
kernel with 2 Xeons. However, 4.1 (FC2) is supposed to be stable with 
SMP kernel. BTW my system is even stable with bigmem smp kernel although 
I've only got 4GB ram. So if I ever have to upgrade to 6GB and run 2 
labs of 30 off the one server I could do it. That's the other nice 
feature of this MB it's got 6 memory slots.

A couple of notes. You MUST disable HostRaid in the bios for the 
controller to work with Linux. Also, I down graded each scsi channel to 
160 mb/s instead of 320 mb/s. The system was not fully stable at 320mb/s 
because of scsi driver issues. Don't worry though a new 10k rpm scsi 
drive only needs around 60 mb/s bandwidth. So you should be okay for 
about 3 drives/channel at full throttle for all of them (highly 
unlikely). I don't think you will ever need more than 6 scsi drives for 
k12ltsp.  The driver for the kernel is written by Justin Gibbs. He had 
some issues/disagreements with James Bottomley (kernel maintainer) and 
Linus Torvalds. So he pulled the drivers before version 2.0.x from his 
site. The 2.6 series kernel has adaptec scsi aic79xx driver 1.3.x in it. 
But if you go with k12ltsp 4.0.1 (FC1 & kernel 2.4.22) or earlier you 
will have to use a driver update disk (DUD) from here


This disk has to be made with dd and must be used during installation of 
the OS in Expert mode.
If you go with k12ltsp 4.1 (FC2) , no worries, it has stable scsi 
adaptec aic79xx driver 1.3.x built in since it comes with kernel 2.6.5
If I was you, I would go with k12ltsp 4.1 (FC2) from the beginning. It 
will be the easiest for you. I did not have this option when I started.

Hope that helps
Good luck

BTW the drivers on adaptec/intel sites are very old (don't use them)

Robert Arkiletian

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